Solar tracker technology has advanced considerably in the past decade. Trackers play an important role in helping the world transition to cleaner energy sources. They optimize the performance of solar power projects.

Trackers are critical to ensuring consistent energy generation. Solar trackers must be engineered to withstand extreme environmental conditions, including both atmospheric and sub-surface corrosion, to perform optimally over a sustained design life.

Corrosion is a pervasive challenge that affects all metallic surfaces and, if not accounted for correctly, can affect the structural integrity of critical components. As solar power projects have become the most cost-effective way to produce power globally, locations for these projects have continued to be pushed into more extreme environments.

Nextracker, a global solar tracking solutions provider, has developed innovative technologies to address corrosion, ensuring that solar projects remain viable and effective under the most demanding conditions. By incorporating advanced corrosion-resistant coatings into the design of metallic components, Nextracker has enhanced solar trackers’ durability, reliability, and performance. There is a lack of consistency in the industry approach to corrosion. Nextracker has gone above and beyond steel coating manufacturers’ recommendations and code requirements to demonstrate leadership in this field.

Solutions for Highly Corrosive Sites

Khavda, a village in the Kutch district of Gujarat, is home to a massive renewable energy park. The project is considered a cornerstone of India’s plans to install 500 GW of renewable energy capacity by 2030. It is located in the extreme landscape of the Great Rann of Kutch, which poses a high risk for metallic structures because of high soil salinity and an arid and corrosive atmosphere.

Solar trackers are mainly made from steel components. Sustained exposure to corrosion may weaken structural strength and reduce the structure’s capacity to withstand an extreme wind event. Traditional coatings for this type of steel structure are galvanized through a zinc coating. Many alternatives, such as higher corrosion-resistant coatings, are available in the market. Still, their effectiveness depends on both the proper application and design of these coatings and the specific site conditions. For highly corrosive sites like Khavda, understanding these factors and selecting proper solutions is mission-critical.

Nextracker has proactively approached this challenge by adopting advanced Zinc-Aluminium-Magnesium (Zn-Al-Mg) coatings. Developed by leading steel manufacturers, these coatings offer superior corrosion resistance compared to traditional zinc coatings like pre-galvanization (pre-galv) and hot-dipped galvanization. However, since the formulations of these advanced coatings are proprietary, there is no industry standard to measure their corrosion resistance, making coating selection a difficult task.

Nextracker developed an extensive test protocol to expose coated parts in an accelerated test chamber to better understand the effect of corrosion on real-world components. The results have allowed Nextracker to confidently deploy trackers in some of the world’s harshest environments.

White Rust vs Red Rust

One of the common concerns raised by EPC and operator-owners of solar power generation plants is the visibility of rust, either white or red rust. While white rust may appear undesirable, it is actually a protective layer over the Zn-Al-Mg coating, extending its life by protecting it from further deterioration. Best practices point to not removing the white rust, which diminishes the coating performance.

Generally, red rust should be seen as a warning sign; however, this greatly depends on the type of coatings used and the component’s design. For example, Zn-Al-Mg coatings have self-healing properties, which enhance the steel structures’ durability by forming a corrosion-resistant protective layer. This ability to self-heal is an advantage of the coatings chosen by Nextracker to provide additional protection to the system, even in cases where red rusting has appeared. Nextracker also provides detailed maintenance protocols to educate customers on the correct maintenance methods and when advanced mitigation efforts are required.

This article is sponsored by solar tracker manufacturer Nextracker and authored by Aditya Morankar, Product Manager at Nextracker, and Raghavendra Praveen Maddulapalli, Assistant Manager of Mechanical Engineering at Nextracker.